CN116457509A

CN116457509A - Filament, structure, resin composition, and method for producing filament

Info

Publication number: CN116457509A
Application number: CN202180068657.XA
Authority: CN
Inventors: 山中政贵; 松本信彦
Original assignee: Mitsubishi Gas Chemical Co Inc
Current assignee: Mitsubishi Gas Chemical Co Inc
Priority date: 2020-10-08
Filing date: 2021-09-01
Publication date: 2023-07-18
Also published as: KR20230084206A; WO2022074966A1; EP4227346A1; JPWO2022074966A1; US20230374706A1; TW202223183A; EP4227346A4

Abstract

Providing: filaments comprising polyamide resin, which have high strength and high retention of mechanical properties after water absorption, structures, resin compositions, and processes for producing the filaments. A filament comprising a polyamide resin comprising a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, wherein 70mol% or more of the diamine-derived structural unit is derived from xylylenediamine, 70mol% or more of the dicarboxylic acid-derived structural unit is derived from an alpha, omega-linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms, and the content of a compound having a molecular weight of 310 to 1000 is 0.1 mass% to 1.5 mass%, and the content of a compound having a molecular weight of less than 310 is 0.1 mass%.

Description

Filament, structure, resin composition, and method for producing filament

Technical Field

The present invention relates to: filaments, structures comprising filaments, resin compositions suitable as raw materials for filaments, and processes for producing filaments. In particular, it relates to filaments comprising a polyamide resin as a main raw material.

Background

Conventionally, filaments using a polyamide resin as a main raw material have been used for various applications. Such polyamide filaments have high strength and thus high usefulness. Therefore, polyamide filaments have been studied for use as structures such as nonwoven fabrics, adsorbents, filter cloths, filter papers, and filters.

However, the conventional polyamide filaments (for example, polyamide filaments using polyamide 66 as a main raw material) have a large decrease in strength due to water absorption, and when used as an aqueous chemical solution treatment filter, the strength from the initial state is significantly decreased.

As a polyamide filament, a polyamide resin composed of meta-xylylenediamine and adipic acid is also disclosed (patent document 1). However, the strength after water absorption is not sufficient.

Prior art literature

Patent literature

Patent document 1: international publication No. 2019/163062

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide: filaments comprising polyamide resin and having high strength and high retention of mechanical properties after water absorption, structures, resin compositions, and processes for producing the filaments.

Solution for solving the problem

Based on the above-described problems, the present inventors have studied and found that: the above problems can be solved by precisely adjusting the amount of the low molecular weight component in the specific polyamide resin.

Specifically, the above problems are solved according to the following means.

<1> a filament comprising a polyamide resin,

the polyamide resin comprises diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70mol% or more of the diamine-derived structural units are derived from xylylenediamine, 70mol% or more of the dicarboxylic acid-derived structural units are derived from an alpha, omega-linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms,

the content of the compound having a molecular weight of 310 to 1000 in the filament is 0.1 to 1.5 mass%,

the content of the compound having a molecular weight of less than 310 is 0.1 mass% or less.

<2> the filament according to <1>, which is drawn.

<3> the filament according to <1> or <2>, wherein the compound having a molecular weight of 310 or more and 1000 or less comprises a cyclic compound formed from xylylenediamine 1 molecules and an α, ω -linear aliphatic dicarboxylic acid 1 molecule having 11 to 14 carbon atoms.

The filament according to any one of <1> to <3>, wherein 30 to 100 mol% of the diamine-derived structural units are derived from m-xylylenediamine and 0to 70mol% are derived from p-xylylenediamine.

The filament according to any one of <1> to <4>, wherein 70mol% or more of the dicarboxylic acid-derived structural unit is 1, 12-dodecanedioic acid.

The filament according to any one of <1> to <5>, wherein the retention rate of the tensile strength of the filament before impregnation with a chemical solution is 90% or more when the filament is subjected to humidity adjustment for 1 week in an environment of 23 ℃ and 50% relative humidity and immersed in hydrochloric acid having a concentration of 10 mass% for 1 week, and the retention rate of the tensile strength of the filament before impregnation with a chemical solution is 90% or more when the filament is subjected to humidity adjustment for 1 week in an environment of 23 ℃ and 50% relative humidity and immersed in an aqueous sodium hydroxide solution having a concentration of 10 mass% for 1 week.

<7>According to<1>～<6>The filament of any one of claims having a denier per filament of 2.0x10 ^-5 ～50dtex。

<8> the filament according to any one of <1> to <7>, which is a multifilament.

<9> a structure comprising the filament of any one of <1> to <8 >.

<10> the structure according to <9>, wherein the structure is a nonwoven fabric, an adsorbent, a filter cloth, a filter paper or a filter.

<11> a resin composition comprising: polyamide resin, and a compound having a molecular weight of 310 to 1000,

the content of the compound having a molecular weight of 310 to 1000 is 0.1 to 1.5 mass%,

further, the content of the compound having a molecular weight of less than 310 is 0.1 mass% or less.

<12> the resin composition according to <11>, which is used for filaments, nonwoven fabrics, adsorbents, filter cloths, filter papers or filters.

<13> a method for producing the filament according to any one of <1> to <8>, comprising the steps of: the resin composition of <11> is spun by a melt spinning method or an electrolytic spinning method.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there may be provided: filaments comprising polyamide resin and having high strength and high retention of mechanical properties after water absorption, structures, resin compositions, and processes for producing the filaments.

Detailed Description

Hereinafter, a mode for carrying out the present invention (hereinafter, simply referred to as "present embodiment") will be described in detail. The present embodiment described below is an example for explaining the present invention, and the present invention is not limited to the present embodiment.

In the present specification, "to" is used in a meaning including numerical values described before and after the "to" as a lower limit value and an upper limit value.

In the present specification, the physical properties and the characteristic values are those at 23℃unless otherwise specified.

The filaments of the present embodiment are characterized by comprising a polyamide resin composed of diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70mol% or more of the diamine-derived structural units are derived from xylylenediamine, 70mol% or more of the dicarboxylic acid-derived structural units are derived from an α, ω -linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms, and the content of a compound having a molecular weight of 310 to 1000 is 0.1 mass% to 1.5 mass%, and the content of a compound having a molecular weight of less than 310 in the filaments is 0.1 mass% or less. By forming this structure, filaments having high strength and high retention of mechanical properties after water absorption are obtained. More specifically, the linear strength was excellent, and the retention of the elastic modulus and tensile strength after water absorption was high. Further, it is excellent in continuous productivity and chemical resistance.

The reason for this is presumed to be as follows. That is, in the filaments of the present embodiment, xylylenediamine and an α, ω -linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms are used as raw material monomers for the polyamide resin. By using the polyamide resin composed of such a raw material, the filaments are less likely to absorb water, and the decrease in mechanical properties can be suppressed. In addition, it is presumed that hydrolysis is not easily caused, and chemical resistance can be lowered. Further, it is estimated that the polyamide resin has improved stretchability and thus can improve the strength of filaments by setting the content of the compound having a molecular weight of 310 to 1000 mass% inclusive to 0.1 mass% to 1.5 mass% inclusive. Further, it is presumed that a compound having a molecular weight of 310 or more and 1000 or less is particularly less likely to come out after immersing in water than a compound having a molecular weight of less than 310, and therefore, the mechanical properties after water absorption can be maintained at a high level.

< Polyamide resin >)

The polyamide resin used in the present embodiment is composed of diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70mol% or more of the diamine-derived structural units are derived from xylylenediamine, 70mol% or more of the dicarboxylic acid-derived structural units are derived from an α, ω -linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms, and the content of a compound having a molecular weight of 310 to 1000 is 0.1 mass% to 1.5 mass%, and the content of a compound having a molecular weight of less than 310 is 0.1 mass%. Hereinafter, in this specification, such a polyamide resin may be referred to as "polyamide resin (a)".

In the polyamide resin (a), 70mol% or more of the diamine-derived structural units are derived from xylylenediamine, preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 99 mol% or more. The upper limit is 100 mol%.

The xylylenediamine preferably contains 10to 100 mol% of m-xylylenediamine and 90 to 0mol% of p-xylylenediamine (wherein the total of m-xylylenediamine and p-xylylenediamine is not more than 100 mol%), more preferably contains 30 to 100 mol% of m-xylylenediamine and 70 to 0mol% of p-xylylenediamine, and still more preferably contains 50 to 100 mol% of m-xylylenediamine and 0to 50 mol% of p-xylylenediamine. In addition, in xylylenediamine, the total amount of m-xylylenediamine and p-xylylenediamine is preferably 95 mol% or more, more preferably 99 mol% or more, and still more preferably 100 mol%.

Examples of diamine components other than xylylenediamine include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentaenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2, 4-trimethyl-hexamethylenediamine, 2, 4-trimethylhexamethylenediamine, etc., diamines having an aromatic ring such as 1, 3-bis (aminomethyl) cyclohexane, 1, 4-bis (aminomethyl) cyclohexane, 1, 3-diaminocyclohexane, 1, 4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (aminomethyl) tricyclodecane, etc., diamines having an aromatic ring such as bis (4-aminophenyl) ether, p-phenylenediamine, bis (aminomethyl) naphthalene, etc., and the like may be used in combination of 1 or 2 or more.

In the polyamide resin (a), 70mol% or more of the constituent units derived from a dicarboxylic acid are derived from an α, ω -linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms (preferably an α, ω -linear aliphatic dicarboxylic acid having 12 to 14 carbon atoms, more preferably 1, 12-dodecanedioic acid). The proportion of the α, ω -linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms in the dicarboxylic acid-derived structural unit is preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 99 mol% or more. The upper limit is 100 mol%.

Examples of the dicarboxylic acid component other than the α, ω -linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms include naphthalene dicarboxylic acids having 10 or less carbon atoms such as succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, and the like, phthalic acid compounds such as isophthalic acid, terephthalic acid, and phthalic acid, 1, 2-naphthalene dicarboxylic acid, 1, 3-naphthalene dicarboxylic acid, 1, 4-naphthalene dicarboxylic acid, 1, 5-naphthalene dicarboxylic acid, 1, 6-naphthalene dicarboxylic acid, 1, 7-naphthalene dicarboxylic acid, 1, 8-naphthalene dicarboxylic acid, 2, 3-naphthalene dicarboxylic acid, 2, 6-naphthalene dicarboxylic acid, and 2, 7-naphthalene dicarboxylic acid, and 1 or 2 or more naphthalene dicarboxylic acids may be used in combination.

The term "structural unit derived from diamine and structural unit derived from dicarboxylic acid" means that an amide bond constituting the polyamide resin (a) is formed by bonding a dicarboxylic acid to a diamine. The polyamide resin (a) contains other sites such as terminal groups in addition to the dicarboxylic acid-derived structural units and diamine-derived structural units. Further, a repeating unit having an amide bond not derived from the bond between the dicarboxylic acid and the diamine, a trace amount of impurities, and the like may be contained in some cases. Specifically, as the polyamide resin (a), aliphatic aminocarboxylic acids such as lactams such as epsilon-caprolactam and laurolactam, and aliphatic aminocaproic acid may be used as the copolymerization component in addition to the diamine component and the dicarboxylic acid component, within a range that does not impair the effects of the present embodiment. In the present embodiment, the polyamide resin (a) preferably has a diamine-derived structural unit or a dicarboxylic acid-derived structural unit in an amount of 90 mass% or more, more preferably 95 mass% or more, and still more preferably 98 mass% or more.

The polyamide resin (a) used in the present embodiment has a molecular weight of 310 to 1000 and a content of 0.1 to 1.5 mass%. By containing a small amount of the compound having such a molecular weight, the stretchability is improved, and the linear strength of the filaments can be improved. Further, since the compound having a molecular weight of 310 or more and 1000 or less is not easily removed from the filaments after water absorption, high mechanical properties can be maintained.

The compound having a molecular weight of 310 to 1000 is not particularly limited in its kind and the like, and is a raw material monomer derived from the polyamide resin (a), an oligomer of other components added during the production of the polyamide resin (a), or the like. In the present embodiment, the compound having a molecular weight of 310 to 1000 preferably includes a cyclic compound composed of xylylenediamine 1 molecules and an α, ω -linear aliphatic dicarboxylic acid 1 molecule having 11 to 14 carbon atoms. By containing a prescribed amount of such a cyclic compound, the effects of the present invention can be more effectively achieved. In particular, when the dicarboxylic acid as a raw material of the polyamide resin is sebacic acid, the cyclic compound formed from xylylenediamine 1 molecules and sebacic acid 1 molecules has a small molecular weight. Further, since the filaments are originally thin, such a cyclic compound easily oozes out of the filaments when immersed in water, and the strength retention rate is easily lowered. In this embodiment, this is avoided by increasing the carbon number of the α, ω -linear aliphatic dicarboxylic acid.

The polyamide resin (a) preferably contains at least a compound having a molecular weight of 310 to 700, more preferably contains at least a compound having a molecular weight of 310 to 500 as a compound having a molecular weight of 310 to 1000.

The content of the compound having a molecular weight of 310 to 1000 mass% is preferably 0.3 mass% or more, more preferably 0.5 mass% or more, still more preferably 0.6 mass% or more, and further preferably 1.2 mass% or less, still more preferably 1.0 mass% or less in the polyamide resin (a).

The polyamide resin (a) may contain only 1 kind, or may contain 2 or more kinds of compounds having a molecular weight of 310 or more and 1000 or less. When the content is 2 or more, the total amount is preferably within the above range.

The polyamide resin (a) used in the present embodiment has a content of a compound having a molecular weight of less than 310 of 0.1 mass% or less. By forming this structure, elution of low molecular weight components when immersed in water can be effectively suppressed. In particular, when the filament according to the present embodiment is used as a filter for filtering an aqueous solution, if the low molecular weight component contained in the filament is likely to flow out when immersed in water, there is a case where a problem in performance as a filter arises. In this embodiment, the content of the compound having a molecular weight of less than 310 is set to 0.1 mass% or less, whereby outflow of such low-molecular-weight components can be effectively suppressed. The lower limit of the content of the compound having a molecular weight of less than 310 is preferably 0 mass%, and the detection limit may be a practical lower limit.

The number average molecular weight (Mn) of the polyamide resin (a) used in the present embodiment is preferably 6000 to 50000, more preferably 8000 to 48000, and still more preferably 9000 to 46000. If the content is within this range, the molding processability becomes more excellent.

The number average molecular weight (Mn) herein can be obtained from a standard polymethyl methacrylate (PMMA) equivalent measured by Gel Permeation Chromatography (GPC).

The polyamide resin (a) used in the present embodiment may or may not have a melting point. In the case of having a melting point, the melting point is preferably 170 to 280 ℃, more preferably 170 to 250 ℃. When the amount is within this range, filaments having more excellent moldability into a structure and more excellent heat resistance can be obtained.

In the present invention, the melting point refers to the temperature of the peak top of the endothermic peak at the time of temperature increase observed by DSC (differential scanning calorimetry). Specifically, the following temperatures are referred to: the sample amount was 1mg using a DSC apparatus, nitrogen gas as an atmosphere gas was flowed at 30 mL/min, and the mixture was heated from room temperature (25 ℃) to a temperature equal to or higher than the intended melting point at a heating rate of 10 ℃/min to melt the mixture, and then the melted polyamide resin was quenched in dry ice, and the temperature of the peak top of the endothermic peak observed when the mixture was again heated to a temperature equal to or higher than the melting point at a heating rate of 10 ℃/min.

In the filament of the present embodiment, the polyamide resin (a) is preferably 70 mass% or more, more preferably 80 mass% or more, further preferably 90 mass% or more, further preferably 95 mass% or more, further preferably 98 mass% or more, based on the mass of the filament.

The filaments of the present embodiment may contain only 1 kind, or may contain 2 or more kinds of polyamide resins (a). When the content is 2 or more, the total amount is preferably within the above range.

< other Components >

The filaments of the present embodiment may contain a polyamide resin other than the polyamide resin (a), a thermoplastic resin other than the polyamide resin, a resin additive, and the like within a range that does not significantly deviate from the effects of the present embodiment.

Examples of the polyamide resin other than the polyamide resin (A) include polyamide 4, polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 6/66, polyamide 610, polyamide 612, polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyamide 66/6T, polyamide 9MT, polyamide 6I/6T, polyamide XD6 (polyhexamethylene adipamide), polyamide XD10 (polyhexamethylene sebacamide), polyamide 10T, 1,3-BAC10I (polyamide resin composed of 1, 3-diaminomethylcyclohexane and sebacic acid and isophthalic acid), 1,4-BAC10I (polyamide resin composed of 1, 4-diaminomethylcyclohexane and sebacic acid and isophthalic acid), and the like, and preferably polyamide 6, polyamide 66, polyamide 666, polyamide 610, polyamide 612.

The filaments of the present embodiment may contain only 1 kind, or may contain 2 or more kinds of polyamide resins other than the polyamide resin (a). When the content is 2 or more, the total amount is preferably within the above range.

Examples of the thermoplastic resin other than the polyamide resin include 1 or 2 or more of polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate resins, polyoxymethylene resins, polyether ketone, polyether sulfone, thermoplastic polyether imide and the like.

In the filaments of the present embodiment, a composition substantially free of thermoplastic resin other than the polyamide resin (a) can be formed. Substantially free means that, for example, the content of the thermoplastic resin other than the polyamide resin (a) in the filament of the present embodiment is 5 mass% or less, preferably 3 mass% or less, and more preferably 1 mass% or less of the content of the polyamide resin (a).

To the filaments of the present embodiment, additives such as antioxidants, heat stabilizers, hydrolysis resistance improvers, weather stabilizers, delustrants, ultraviolet absorbers, nucleating agents, plasticizers, dispersants, flame retardants, antistatic agents, coloring resists, antigelling agents, mold release agents, surfactants, and coloring agents may be added within a range that does not impair the object/effect of the present embodiment. Details thereof are incorporated herein by reference to the descriptions of paragraphs 0130 to 0155 of Japanese patent publication No. 4894982, paragraph 0021 of Japanese patent application laid-open No. 2010-281027, and paragraph 0036 of Japanese patent application laid-open No. 2016-223037.

The filaments of the present embodiment do not contain a plasticizer, or the content of the plasticizer may be less than 0.5 parts by mass, preferably 0.4 parts by mass or less with respect to 100 parts by mass of the polyamide resin. In this embodiment, since a compound having a molecular weight of 310 or more and 1000 or less functions as a plasticizer, such a constitution can be formed.

The filaments of the present embodiment are adjusted so that the total of the polyamide resin (a), the compound having a molecular weight of 310 to 1000, and other components (thermoplastic resin, additive, etc.) to be blended as needed is 100 mass%.

< morphology and Properties of filaments >)

The filaments of the present embodiment may be monofilaments or multifilaments, but are preferably multifilaments. The multifilament is formed, and thus the processing into a structure becomes easy.

When the filaments of the present embodiment are multifilament, the number of filaments constituting one multifilament is preferably 10 or more, more preferably 20 or more, and may be 30 or more. The upper limit of the number of filaments constituting one multifilament is preferably 100 or less, more preferably 60 or less, and still more preferably 55 or less. By setting the range as described above, unevenness in filament fineness during spinning can be suppressed, and welding between filaments during spinning can be prevented.

The filaments of this embodiment are generally circular in cross-section. The term "circular" as used herein means that the technical field of the present embodiment includes a circular shape, as well as a geometric circular shape. The cross section of the filament in the present embodiment may be a shape other than a circle, for example, may be a flat shape such as an ellipse or an oblong.

The filament of the present embodiment preferably has a denier per filament of 2.0X10 ^-5 50dtex. By setting the lower limit value to be equal to or higher than the above, stable spinning can be performed, and the structure can have sufficient strength when processed into the structure. In addition, by setting the upper limit value or less, the pore size at the time of forming the structure can be reduced, and not only the dust removal performance is improved, but also the pressure loss can be effectively suppressed. The lower limit of the fineness of the single yarn is preferably 8.0X10 ^-5 dtex or more, more preferably 9.0X10 ^-3 dtex or more, more preferably 1.0X10 ^-2 dtex or more, more preferably 0.5dtex or more, still more preferably 1dtex or more. The upper limit of the fineness of the single yarn is preferably 40dtex or less, more preferably 30dtex or less, still more preferably 25dtex or less, still more preferably 20dtex or less, still more preferably 18dtex or less.

In addition, the fineness of the filaments of the present embodiment is preferably 10to 1000dtex when the filaments are multifilament. By setting the lower limit value to be equal to or higher than the above, stable spinning can be performed, and the structure can have sufficient strength when processed into the structure. In addition, by setting the upper limit value or less, the pore size at the time of forming the structure can be reduced, and not only the dust removal performance is improved, but also the pressure loss can be effectively suppressed. The lower limit of the fineness of the multifilament is preferably 40dtex or more, more preferably 60dtex or more, and still more preferably 100dtex or more. The fineness of the multifilament yarn is preferably 800dtex or less, more preferably 600dtex or less, and still more preferably 400dtex or less.

The fineness was measured by the method described in examples described below.

The filament length (mass average length) of the present embodiment is not particularly limited, but is preferably 5mm or more, more preferably 0.1m or more, further preferably 1m or more, and further preferably 100m or more. The upper limit value of the length (mass average length) of the filaments is preferably 20000m or less, more preferably 1000m or less, and further preferably 100m or less.

The filaments of this embodiment may or may not be drawn, but are preferably drawn. By stretching, filaments having more excellent mechanical strength are obtained. The stretching is preferably performed in the longitudinal direction of the filaments (filament length direction). The stretching ratio is preferably 2.0 times or more, more preferably 2.5 times or more, still more preferably 3.0 times or more, and still more preferably 3.5 times or more. The upper limit of the stretching ratio is preferably 6.5 times or less, more preferably 6.0 times or less, still more preferably 5.5 times or less, and still more preferably 5.0 times or less.

The filaments of this embodiment preferably have excellent strength.

Specifically, according to JIS L1013:2010, the linear strength of the filaments is preferably 4.25cN/dtex or more, more preferably 4.30cN/dtex or more, still more preferably 4.35cN/dtex or more. The upper limit of the linear strength is not particularly limited, but is practically 6.50cN/dtex or less.

The filaments of the present embodiment preferably have excellent water absorbency.

Specifically, the filament is dried at 80 ℃ for 24 hours, and the retention of tensile strength when immersed in water at 23 ℃ for 1 week is preferably 85% or more, more preferably 90% or more. The upper limit of the retention rate is preferably 100%, but 99.9% or less is practical.

The filaments of the present embodiment are also preferably excellent in chemical resistance.

Specifically, the retention rate of the tensile strength of the filaments before impregnation with a chemical solution after humidity adjustment for 1 week at 23 ℃ under a relative humidity of 50% is preferably 90% or more, more preferably 91% or more, when the filaments are impregnated with hydrochloric acid having a concentration of 10 mass% for 1 week. The upper limit of the retention rate is preferably 100%, but 99.9% or less is practical.

The retention rate of the tensile strength of the filaments before impregnation with a chemical solution after humidity adjustment for 1 week at 23 ℃ under a relative humidity of 50% is preferably 90% or more, more preferably 91% or more, when the filaments are immersed in a 10 mass% aqueous sodium hydroxide solution for 1 week. The upper limit of the retention rate is preferably 100%, but 99.9% or less is practical.

In the present embodiment, it is sufficient that either the retention rate after the hydrochloric acid impregnation or the retention rate after the sodium hydroxide aqueous solution impregnation is satisfied, and both are preferably satisfied. Further, the retention rate after the water absorption is preferably also satisfied.

< method for producing filaments >)

Next, a method for producing the filament according to the present embodiment will be described.

The filaments in this embodiment are obtained by molding the resin composition. The molding method is arbitrary, and the molded article can be molded into a desired shape by an arbitrary molding method known in the art. For example, the descriptions of paragraphs 0051 to 0058 of International publication No. 2017/010389 may be referred to, and these descriptions are incorporated into the present specification.

In this embodiment, the filaments are particularly preferably produced by a melt spinning method or an electrospinning method. The melt spinning method is a method of extruding from a porous die with an extruder and stretching by a roll. In addition, the electrospinning method is a method in which a resin is dissolved in a solvent, and when the dissolved resin solution is discharged from a fine nozzle, an electric field is applied to the resin solution at the position of an outlet, the resin solution itself is also charged, and the solvent is volatilized while being stretched by a potential difference.

< Structure >)

The structure of the present embodiment includes the filaments of the present embodiment. The structure of the present embodiment includes the filaments of the present embodiment in the form of a filament. The term "holding" as used herein means holding a substantially filament shape, and includes a case where a part of the filament (for example, 10 vol% or less thereof) is melted and bonded to other filaments or other constituent materials (other fibers, base materials, etc.) possibly included in the structure.

The structure of the present embodiment may be a filament material such as a mixed filament including the filaments of the present embodiment, a string, a strand, a spun yarn, or a filament having a core-sheath structure. In the case of forming a hybrid filament or the like, it is preferable to combine with other thermoplastic resin filaments, carbon fibers, reinforcing fibers (filaments) such as glass fibers, or the like.

The structure of the present embodiment is preferably a filament, nonwoven fabric, adsorbent, filter cloth, filter paper or filter including the filament of the present embodiment. The filaments, nonwoven fabrics, adsorbents, filter cloths, filter papers, or filters according to the present embodiment are also intended to include filaments such as mixed filaments, ropes, and plaits using the filaments according to the present embodiment, nonwoven fabrics, adsorbents, filter cloths, filter papers, or filters, and the like.

An example of the structure of the present embodiment is a flat plate-like structure composed only of a layer containing filaments of the present embodiment as a main component. Another example of the structure of the present embodiment is a multilayer body of a layer containing the filaments of the present embodiment as a main component and a base material. The structure of the present embodiment may be a multilayer body of a layer containing filaments of the present embodiment as a main component, other nonwoven fabrics, filters, and the like. The layer containing the filaments according to the present embodiment as the main component means that the component having the largest content in the constituent structure of the layer is the filaments according to the present embodiment. Examples of the other nonwoven fabric, filter, and the like include nonwoven fabrics made of polyolefin (preferably polypropylene), and filters.

When the structure of the present embodiment is used as a filter, the substance to be treated is not particularly limited, and examples include water-treated sludge, gel, protein, and polysaccharide substance LPS that needs to be removed in reuse of seawater.

When the structure of the present embodiment is used as a filter, the density is preferably 1.10 to 1.25g/cm ³ . The pore diameter of the filter is preferably 0.001 to 500. Mu.m.

As a method for manufacturing the above filter, an air flow method and a melt blowing method are exemplified. The air flow method is a method of extruding filaments from a porous die, and blowing the filaments, which are melted and solidified by an air flow, onto a substrate in a net shape. The melt blowing method is a method of extruding a resin composition in a molten state and blowing the resin composition onto a substrate in a web form.

< resin composition >)

Next, the resin composition of the present embodiment will be described.

The resin composition of the present embodiment includes: a polyamide resin comprising a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, wherein 70mol% or more of the diamine-derived structural unit is derived from xylylenediamine, 70mol% or more of the dicarboxylic acid-derived structural unit is derived from an α, ω -linear aliphatic dicarboxylic acid having 11 to 14 carbon atoms, and the content of the compound having a molecular weight of 310 to 1000 is 0.1 mass% to 1.5 mass%, and the content of the compound having a molecular weight of less than 310 is 0.1 mass% or less. Such a resin composition is preferably used for producing filaments, nonwoven fabrics, adsorbents, filter cloths, filter papers, or filters according to the present embodiment.

The details and other components of the polyamide resin (a) in the resin composition of the present embodiment are the same as those of the filaments of the present embodiment described above, and the preferable ranges are also the same.

Examples

The present invention will be further specifically described with reference to the following examples. The materials, amounts, ratios, treatment contents, treatment steps and the like shown in the following examples may be appropriately changed without departing from the gist of the present invention. Accordingly, the scope of the present invention is not limited to the specific examples shown below.

In the case where the measurement apparatus or the like used in the examples is difficult to obtain due to production stoppage or the like, measurement may be performed using other apparatuses having equivalent performance.

Example 1

< Synthesis of Polyamide MP12 >

In a jacketed reaction kettle provided with a stirrer, a dephlegmator, a condenser, a thermometer, a liquid dropping tank and a nitrogen inlet pipe, 60.00mol of precisely weighed 1, 12-dodecanedioic acid is placed into the jacketed reaction kettle, the nitrogen is fully replaced, and the temperature is further raised to 180 ℃ under a small amount of nitrogen flow, so that the 1, 12-dodecanedioic acid is dissolved, and a uniform flowing state is formed. To this, 60mol of p/m-xylylenediamine, in which 30mol% of the diamine component was p-xylylenediamine and 70mol% was m-xylylenediamine, was added dropwise over 160 minutes with stirring. During this time, the internal pressure of the reaction system was set at normal pressure, the internal temperature was continuously raised to 250 ℃, and p/m-xylylenediamine was added dropwise while the distilled water was discharged to the outside of the system through a dephlegmator and a condenser. After the p/m-xylylenediamine was added dropwise, the reaction was continued for 10 minutes while maintaining the liquid temperature at 250 ℃. Then, the internal pressure of the reaction system was continuously reduced to 600Torr within 10 minutes, and then the reaction was continued for 30 minutes, whereby the component amount having a molecular weight of 1000 or less was adjusted. During this time, the reaction temperature was continuously raised to 260 ℃. After the reaction was completed, a pressure of 0.3MPa was applied to the reactor with nitrogen, and the polymer was taken out from the nozzle at the lower part of the polymerization vessel as a strand, water-cooled, and cut into pellet shapes to obtain pellets of a molten polymer. The obtained pellets were put into a drum (rotary vacuum tank) having a jacket heated by a heat medium at room temperature. While the drum was rotated, the inside of the vessel was depressurized (0.5 to 10 Torr), the circulating heat medium was heated to 150℃and the pellet temperature was raised to 130℃and kept at that temperature for 3 hours. Thereafter, nitrogen gas was again introduced to set the pressure at normal pressure, and cooling was started. When the temperature of the pellets was 70℃or lower, the pellets were taken out of the tank to obtain a solid-phase polymer.

The melting point of the polyamide resin (MP 12) obtained was 206 ℃.

< production of Polyamide filaments >

The polyamide resin shown in Table 1 was melted by a single screw extruder, the spinning temperature was set to 290℃and the resultant was spun through a spinneret (the number of holes is shown in Table 1). After passing the spun polyamide filaments through the heating zone and the cooling zone, the polyamide filaments (hereinafter, sometimes referred to as "pre-drawing filaments") which have been brought to substantially room temperature are immersed in a bundling agent (DELION PP-807, manufactured by Bambusa Corp.) to form bundles, and then are collected by a non-heated roller 1, and are drawn continuously without being wound up temporarily. The pre-drawn filament taken up using the roll 1 was heated by the roll 2 heated to 80 c, and then, after passing through the rolls 2,3 and 4 heated to 170 c, was wound up by a winder. At this time, the speed ratio was set between the rolls 2 and 3, and the stretching was performed, and the speed ratio was adjusted so as to be the stretch ratio shown in table 1. Further, a speed ratio is set between the roller 3 and the roller 4 to relax, and the rotation speed of the roller 4 is set to be 4% slower than the roller 3.

< determination of oligomer >)

The amount of the oligomer having a molecular weight of less than 310 and the amount of the oligomer having a molecular weight of 310 to 1000 are determined from a standard polymethyl methacrylate (PMMA) conversion value measured by Gel Permeation Chromatography (GPC) as follows.

For the column, 2 filled styrene polymers were used as a filler, and Hexafluoroisopropanol (HFIP) having a sodium trifluoroacetate concentration of 2mmol/L was used as a solvent, and the resin concentration was measured at 0.02 mass%, the column temperature was 40℃and the flow rate was 0.3 mL/min, and the refractive index was measured by a refractive index detector (RI). In addition, a standard curve was prepared by dissolving 6 levels of PMMA in HFIP and measuring. The amount of the oligomer having a molecular weight of less than 310 and the amount of the oligomer having a molecular weight of 310 to 1000 are expressed as the amount (% by mass) relative to the total amount of the polyamide resin having a molecular weight of more than 1000. Here, although each component obtained by GPC is obtained as area%, the area% can be regarded as equivalent to mass%, and thus the above values are described as mass%.

The gel permeation chromatography apparatus used in this example was "HLC-8320GPC" manufactured by Tosoh Co., ltd (TOSOH CORPORATION), and the column for measurement was "TSKgel SuperHM-H".

< titre >

According to JIS L1013:2010, the fineness of the filaments (single filament fineness, multifilament fineness) was measured. Units are expressed in dtex.

< continuous spinnability >)

The contamination adhesion of the nozzle after spinning was confirmed, and the adhesion of the components having a molecular weight of 330 or less to the nozzle was evaluated as follows. The evaluation was performed by 5 experts and the judgment was made in a majority voting manner.

A: no attachments, or substantially no attachments.

B: other than a, for example, the attached matter affects the continuous spinning property.

< straight line Strength >

According to JIS L1013:2010, the linear strength of the filaments is measured.

Units are denoted cN/dtex.

< Water absorption resistance >)

Filaments dried at 80℃for 24 hours in a vacuum dryer were immersed in water at 23℃for 1 week, and the retention of tensile strength before immersion in water was evaluated. Tensile strength according to JIS L1013: 2010.

Tensile strength retention = [ (tensile strength before water immersion-tensile strength after water immersion)/tensile strength before water immersion ] ×100 (unit:%)

Units are expressed in%.

< chemical resistance >)

The retention rate of tensile strength of the filaments before immersion in a chemical solution (10 mass% aqueous hydrochloric acid solution or 10 mass% aqueous sodium hydroxide solution) was evaluated after humidity conditioning of the filaments at 23℃for 1 week in an environment having a relative humidity of 50%. Tensile strength according to JIS L1013: 2010.

Tensile strength retention = [ (tensile strength before chemical solution impregnation-tensile strength after chemical solution impregnation)/tensile strength before chemical solution impregnation ] ×100

Units are expressed in%.

Example 2

The procedure was carried out in the same manner as in example 1 except that the polyamide resin was changed to polyamide MXD12, which is shown in the following synthesis example.

< Synthesis of Polyamide MXD12 >

In a jacketed reaction kettle provided with a stirrer, a dephlegmator, a condenser, a thermometer, a liquid dropping tank and a nitrogen inlet pipe, 60.00mol of precisely weighed 1, 12-dodecanedioic acid is placed into the jacketed reaction kettle, the nitrogen is fully replaced, and the temperature is raised to 180 ℃ under a small amount of nitrogen flow, so that the 1, 12-dodecanedioic acid is dissolved, and a uniform flowing state is formed. To this, 60mol of m-xylylenediamine was added dropwise with stirring over 160 minutes. During this period, the internal pressure of the reaction system was set at normal pressure, the internal temperature was continuously raised to 250 ℃, and water distilled off while m-xylylenediamine was added dropwise was discharged to the outside of the system through a dephlegmator and a condenser. After the completion of the m-xylylenediamine addition, the reaction was continued for 10 minutes while maintaining the liquid temperature at 250 ℃. Then, the internal pressure of the reaction system was continuously reduced to 600Torr within 10 minutes, and then the reaction was continued for 30 minutes, whereby the component amount having a molecular weight of 1000 or less was adjusted. During this time, the reaction temperature was continuously raised to 260 ℃. After the reaction was completed, a pressure of 0.3MPa was applied to the reactor with nitrogen, and the polymer was taken out from the nozzle at the lower part of the polymerization vessel as a strand, water-cooled, and cut into pellet shapes to obtain pellets of a molten polymer. The obtained pellets were put into a drum (rotary vacuum tank) having a jacket heated by a heat medium at room temperature. While the drum was rotated, the inside of the vessel was depressurized (0.5 to 10 Torr), the circulating heat medium was heated to 150℃and the pellet temperature was raised to 130℃and kept at that temperature for 3 hours. Thereafter, nitrogen gas was again introduced to set the pressure at normal pressure, and cooling was started. When the temperature of the pellets was 70℃or lower, the pellets were taken out of the tank to obtain a solid-phase polymer.

The melting point of the polyamide resin (MXD 12) obtained was 190 ℃.

Comparative example 1

The procedure was carried out in the same manner as in example 1 except that the polyamide resin was changed to polyamide MP10 shown in the following synthesis example.

< synthetic example of Polyamide MP10 (M/P ratio=7:3) >

In a jacketed reaction vessel equipped with a stirrer, a dephlegmator, a condenser, a thermometer, a liquid drop tank, and a nitrogen inlet tube, sebacic acid was placed, and after heating and dissolving in a nitrogen atmosphere, the contents were stirred while being pressurized (0.35 MPa), so that the molar ratio of diamine to sebacic acid became about 1:1, the molar ratio of m-xylylenediamine to p-xylylenediamine was slowly added dropwise at 7:3 (Mitsubishi gas chemical Co., ltd.) and the temperature was raised to 235 ℃. After completion of the dropwise addition, the reaction was continued for 60 minutes to adjust the component amounts having a molecular weight of 1000 or less. After the completion of the reaction, the content was taken out in the form of strands, and pelletized in a pelletizer to obtain a polyamide resin (MP 10, M/p=7:3).

The melting point of the polyamide resin (MP 10) obtained was 215 ℃.

Comparative example 2

The procedure was carried out in the same manner as in example 1 except that the polyamide resin was changed to PA66 (nylon 66, amilan CM3001, manufactured by Toli Co., ltd., melting point 265 ℃).

Comparative example 3

The procedure was carried out in the same manner as in example 1 except that the polyamide resin was changed to polyamide MP12 shown in the following synthesis example.

< Synthesis of Polyamide MP12 >

Into a SUS-made separable flask having an internal volume of 3L, 1kg of a polyamide resin (MP 12) obtained by the same synthesis method as described in example 1 was placed, and 1.5L of methanol was charged, and the contents were stirred and heated by a mantle heater so that the liquid temperature of methanol became 60 ℃. After heating for 5 hours from the time when the liquid temperature of methanol reached 60 ℃, the mixture was cooled to room temperature, and then the methanol phase was separated from the pellet by passing through a 40-mesh metal mesh. The above operation was repeated a total of 3 times for the separated pellets, and then dried in a vacuum dryer at 120℃for 5 hours, thereby obtaining a resin used in comparative example 3.

Comparative example 4

< Synthesis of Polyamide MP12 >

To a polyamide resin (MP 12) obtained by the same synthesis method as described in example 1,1 mass% of an oligomer having a molecular weight of 310 to 1000 was added, and dry-blended to obtain a resin used in comparative example 4. The oligomer having a molecular weight of 310 to 1000 was obtained by evaporating and solidifying the methanol phase after the treatment described in comparative example 3.

TABLE 1

In the above table, "<0.1" means less than 0.1 mass%.

From the above results, it was revealed that the filaments of the present invention were excellent in linear strength and high in retention of tensile strength after water absorption (examples 1 and 2). Further, the continuous productivity and chemical resistance were also excellent.

On the other hand, in the case of using a polyamide resin composed of xylylenediamine and sebacic acid (α, ω -linear aliphatic dicarboxylic acid having 10 carbon atoms) (comparative example 1), both the linear strength and the retention rate of the tensile strength after water absorption are poor. Further, the continuous productivity is also poor.

In the case of using polyamide 66 (comparative example 2), the linear strength was excellent, but the retention rate of the tensile strength after water absorption was significantly poor. Furthermore, chemical resistance (hydrochloric acid resistance) is also remarkably poor.

The linear strength was poor in the case of using a polyamide resin having a compound content of 310 to 1000 mass% inclusive (comparative example 3) and in the case of using a polyamide resin having a compound content of more than 1.5 mass% inclusive (comparative example 4).

Claims

1. A filament comprising a polyamide resin,

2. The filament according to claim 1, which is drawn.

3. The filament according to claim 1 or 2, wherein the compound having a molecular weight of 310 or more and 1000 or less comprises a cyclic compound formed from xylylenediamine 1 molecules and an α, ω -linear aliphatic dicarboxylic acid 1 molecule having 11 to 14 carbon atoms.

4. The filament according to any one of claims 1 to 3, wherein 30 to 100 mol% of the diamine-derived structural units are derived from m-xylylenediamine and 0to 70mol% are derived from p-xylylenediamine.

5. The filament according to any one of claims 1 to 4, wherein 70mol% or more of the dicarboxylic acid-derived structural units is 1, 12-dodecanedioic acid.

6. The filament according to any one of claims 1 to 5, wherein a retention rate of the filament with respect to a tensile strength before impregnation with a chemical solution is 90% or more when the filament is impregnated with hydrochloric acid having a concentration of 10 mass% for 1 week after humidity adjustment for 1 week at 23 ℃ and a retention rate of the filament with respect to a tensile strength before impregnation with a chemical solution is 90% or more when the filament is impregnated with an aqueous sodium hydroxide solution having a concentration of 10 mass% for 1 week after humidity adjustment for 1 week at 23 ℃ and a relative humidity of 50%.

7. According to claim1-6, the filament having a denier per filament of 2.0X10 ^-5 ～50dtex。

8. The filament according to any one of claims 1 to 7, which is a multifilament yarn.

9. A structure comprising the filament of any one of claims 1 to 8.

10. The structure of claim 9, wherein the structure is a nonwoven fabric, an adsorbent, a filter cloth, a filter paper, or a filter.

11. A resin composition comprising: polyamide resin, and a compound having a molecular weight of 310 to 1000,

12. The resin composition according to claim 11, which is used for filaments, nonwoven fabrics, adsorbents, filter cloths, filter papers or filters.

13. A method of manufacturing the filament according to any one of claims 1 to 8, comprising the steps of: the resin composition according to claim 11 is spun by a melt spinning method or an electrolytic spinning method.